1. Field of the Invention
The invention relates generally to a method of permanent hair removal using laser light. More specifically, the invention relates to the transcutaneous use of laser light to target the keratin component of hair, thus destroying the hair by photothermolysis without damage to surrounding skin or tissue.
2. Description of the Prior Art
Currently available laser hair removal methods may be classified as either intrafollicular or transcutaneous in nature. Intrafollicular methods comprise the delivery of laser light through a small probe tip to the hair follicle. The light utilized is of a wavelength which is readily absorbed by either the melanin in the hair or the hemoglobin in the blood vessels surrounding the papilla. This absorption of light energy produces heat, resulting in damage to the hair shaft, photocoagulation of the tissue surrounding the papilla, and subsequent destruction of the hair. Because the light energy employed in this method is absorbed by either blood or melanin in the skin, it requires the use of a very narrow beam of light to target a single hair at a time and prevent damage to the surrounding tissue. This results in a painstaking, time-consuming process which must be administered by a skilled operator. When targeting melanin, this method losses effectiveness when used on lighter haired or darker skinned patients. In addition, some methods in this category require that the needle-like probe tip be inserted into the hair follicle, a painful process which must be repeated for every hair.
Transcutaneous laser hair removal methods currently available utilizes a substance which is massaged into the skin to penetrate the hair ducts. After cleaning the substance from the skin""s surface, light of a wavelength which passes through the skin, but which is absorbed by the substance, is directed onto the treated area. The absorption of energy by the substance applied to the hair duct causes photocoagulation of the tissue surrounding the papilla and results in destruction of the hair. Although this method allows for treatment of a sizeable area of skin, it requires the inconvenient, time consuming application of the light-absorbing substance. In addition, great care must be taken to completely remove the substance from the skin""s surface prior to the laser treatment to avoid damage to the skin.
Because of the disadvantages associated with both methods of hair removal in use today, a new method is needed which provides faster, more convenient, and less painful permanent hair removal without damage to the patient""s skin.
The invention relates to a method of permanent hair removal used primarily for cosmetic purposes. This method comprises the transcutaneous use of laser light having wavelength in the 900-950 nanometer range wherein the light is directed onto an area of skin on which hair removal is desired. Light of this wavelength passes through the skin with only minimal absorption by blood, blood components, and melanin. This wavelength is, however, readily absorbed by the protein keratin, the main component of hair of all colors. Absorption of the light energy by the keratin produces heat, which damages the hair shaft and root and photocoagulates the blood vessels and tissue surrounding the papilla, resulting in destruction of the hair and preventing its re-growth.
In its preferred embodiment, the method also includes the use of a second wavelength of laser light produced by known means, such as second harmonic generation or 3-mixing plus second harmonic generation, from the same laser source which generates the primary 900-950 nm wavelength. This second wavelength of light, which will be in the 450-475 nanometer range, is readily absorbed by both blood components and melanin. An intrafollicular probe is used to deliver the second wavelength of light to the hair follicle, in the manner described in the prior art, to treat the small percentage of hairs having papillae at a skin depth beyond the effective range of the primary wavelength of light. In this fashion, a single laser light source can be used to treat all types of hair in the least painful and most efficient, cost effective, and convenient manner possible.
There are numerous problems associated with the hair removal methods in the field of prior art. Some of these methods are painful for the patient. Others have varying effectiveness depending on the skin and hair color of the patient. Most must be administered by highly skilled operators to reduce the risk to the patient. All of these methods involve expensive, painstaking, and time-consuming processes. In addition, all carry substantial risk of skin damage if not performed properly.
It is an object of the invention to provide a hair removal method which: 1) is fast and convenient; 2) is less painful; 3) is effective on hair of all types; 4) has reduced risk for skin damage; and 5) utilizes a low cost, low maintenance, and low power consumption laser source. Further objects and advantages of the invention will become apparent from a consideration of the drawings and description.